fd: hide _fdrop 0 count check behind INVARIANTS

While here use refcount_load and make sure to report the tested value.

vfs: support lockless dirfd lookups

cache: fix pwd use-after-free in setting up fallback

Since the code exits smr section prior to calling pwd_hold, the used
pwd can be freed and a new one allocated with the same address, making
the c

cache: fix pwd use-after-free in setting up fallback

Since the code exits smr section prior to calling pwd_hold, the used
pwd can be freed and a new one allocated with the same address, making
the comparison erroneously true.

Note it is very unlikely anyone ran into it.

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Do not copy vp into f_data for DTYPE_VNODE files.

The pointer to vnode is already stored into f_vnode, so f_data can be
reused. Fix all found users of f_data for DTYPE_VNODE.

Provide finit_vnode()

Do not copy vp into f_data for DTYPE_VNODE files.

The pointer to vnode is already stored into f_vnode, so f_data can be
reused. Fix all found users of f_data for DTYPE_VNODE.

Provide finit_vnode() helper to initialize file of DTYPE_VNODE type.

Reviewed by: markj (previous version)
Discussed with: freqlabs (openzfs chunk)
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26346

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fd: fix fhold on an uninitialized var in fdcopy_remapped

Reported by: gcc9

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

fd: pwd_drop after releasing filedesc lock

Fixes a potential LOR against vnode lock.

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

fd: put back FILEDESC_SUNLOCK to pwd_hold lost during rebase

Reported by: pho

vfs: add the infrastructure for lockless lookup

Reviewed by: kib
Tested by: pho (in a patchset)
Differential Revision: https://reviews.freebsd.org/D25577

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

fd: remove fd_lastfile

It keeps recalculated way more often than it is needed.

Provide a routine (fdlastfile) to get it if necessary.

Consumers may be better off with a bitmap iterator instead.

fd: add obvious branch predictions to fdalloc

fd: stop looping in pwd_hold

We don't expect to fail acquiring the reference unless running into a corner
case. Just in case ensure forward progress by taking the lock.

Reviewed by: kib, markj
Diff

fd: stop looping in pwd_hold

We don't expect to fail acquiring the reference unless running into a corner
case. Just in case ensure forward progress by taking the lock.

Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D25616

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vfs: track sequential reads and writes separately

For software like PostgreSQL and SQLite that sometimes reads sequentially
while also writing sequentially some distance behind with interleaved
sysc

vfs: track sequential reads and writes separately

For software like PostgreSQL and SQLite that sometimes reads sequentially
while also writing sequentially some distance behind with interleaved
syscalls on the same fd, performance is better on UFS if we do
sequential access heuristics separately for reads and writes.

Patch originally by Andrew Gierth in 2008, updated and proposed by me with
his permission.

Reviewed by: mjg, kib, tmunro
Approved by: mjg (mentor)
Obtained from: Andrew Gierth <andrew@tao11.riddles.org.uk>
Differential Revision: https://reviews.freebsd.org/D25024

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pwd: unbreak repeated calls to set_rootvnode

Prior to the change the once set pointer would never be updated.

Unbreaks reboot -r.

Reported by: Ross Gohlke

Mark closefrom(2) COMPAT12, reimplement in libc to wrap close_range

Include a temporarily compatibility shim as well for kernels predating
close_range, since closefrom is used in some critical areas

Mark closefrom(2) COMPAT12, reimplement in libc to wrap close_range

Include a temporarily compatibility shim as well for kernels predating
close_range, since closefrom is used in some critical areas.

Reviewed by: markj (previous version), kib
Differential Revision: https://reviews.freebsd.org/D24399

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close_range/closefrom: fix regression from close_range introduction

close_range will clamp the range between [0, fdp->fd_lastfile], but failed
to take into account that fdp->fd_lastfile can become -

close_range/closefrom: fix regression from close_range introduction

close_range will clamp the range between [0, fdp->fd_lastfile], but failed
to take into account that fdp->fd_lastfile can become -1 if all fds are
closed. =-( In this scenario, just return because there's nothing further we
can do at the moment.

Add a test case for this, fork() and simply closefrom(0) twice in the child;
on the second invocation, fdp->fd_lastfile == -1 and will trigger a panic
before this change.

X-MFC-With: r359836

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Implement a close_range(2) syscall

close_range(min, max, flags) allows for a range of descriptors to be
closed. The Python folk have indicated that they would much prefer this
interface to closefrom

Implement a close_range(2) syscall

close_range(min, max, flags) allows for a range of descriptors to be
closed. The Python folk have indicated that they would much prefer this
interface to closefrom(2), as the case may be that they/someone have special
fds dup'd to higher in the range and they can't necessarily closefrom(min)
because they don't want to hit the upper range, but relocating them to lower
isn't necessarily feasible.

sys_closefrom has been rewritten to use kern_close_range() using ~0U to
indicate closing to the end of the range. This was chosen rather than
requiring callers of kern_close_range() to hold FILEDESC_SLOCK across the
call to kern_close_range for simplicity.

The flags argument of close_range(2) is currently unused, so any flags set
is currently EINVAL. It was added to the interface in Linux so that future
flags could be added for, e.g., "halt on first error" and things of this
nature.

This patch is based on a syscall of the same design that is expected to be
merged into Linux.

Reviewed by: kib, markj, vangyzen (all slightly earlier revisions)
Differential Revision: https://reviews.freebsd.org/D21627

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kern_dup(): Call filecaps_free_prep() in a write section.

filecaps_free_prep() bzeros the capabilities structure and we need to be
careful to synchronize with unlocked readers, which expect a consis

kern_dup(): Call filecaps_free_prep() in a write section.

filecaps_free_prep() bzeros the capabilities structure and we need to be
careful to synchronize with unlocked readers, which expect a consistent
rights structure.

Reviewed by: kib, mjg
Reported by: syzbot+5f30b507f91ddedded21@syzkaller.appspotmail.com
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24120

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Merge ^/head r358731 through r358831.

fd: use smr for managing struct pwd

This has a side effect of eliminating filedesc slock/sunlock during path
lookup, which in turn removes contention vs concurrent modifications to the fd
table.

Re

fd: use smr for managing struct pwd

This has a side effect of eliminating filedesc slock/sunlock during path
lookup, which in turn removes contention vs concurrent modifications to the fd
table.

Reviewed by: markj, kib
Differential Revision: https://reviews.freebsd.org/D23889

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Merge ^/head r358466 through r358677.

fd: move vnodes out of filedesc into a dedicated structure

The new structure is copy-on-write. With the assumption that path lookups are
significantly more frequent than chdirs and chrooting this is

fd: move vnodes out of filedesc into a dedicated structure

The new structure is copy-on-write. With the assumption that path lookups are
significantly more frequent than chdirs and chrooting this is a win.

This provides stable root and jail root vnodes without the need to reference
them on lookup, which in turn means less work on globally shared structures.
Note this also happens to fix a bug where jail vnode was never referenced,
meaning subsequent access on lookup could run into use-after-free.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23884

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fd: make fgetvp_rights work without the filedesc lock

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23883